void bcp_implementation::create_path(const fs::path& p)
{
   if(!fs::exists(m_dest_path / p))
   {
      // recurse then create the path:
      create_path(p.branch_path());
      fs::create_directory(m_dest_path / p);
   }
}
void bcp_implementation::copy_path(const fs::path& p)
{
   assert(!fs::is_directory(m_boost_path / p));
   if(fs::exists(m_dest_path / p))
   {
      std::cout << "Copying (and overwriting) file: " << p.string() << "\n";
     fs::remove(m_dest_path / p);
   }
   else
      std::cout << "Copying file: " << p.string() << "\n";
   //
   // create the path to the new file if it doesn't already exist:
   //
   create_path(p.branch_path());
   //
   // do text based copy if requested:
   //
   if(p.leaf() == "Jamroot")
   {
      static std::vector<char> v1, v2;
      v1.clear();
      v2.clear();
      std::ifstream is((m_boost_path / p).c_str());
      std::copy(std::istreambuf_iterator<char>(is), std::istreambuf_iterator<char>(), std::back_inserter(v1));

      static boost::regex libname_matcher;
      if(libname_matcher.empty())
      {
         libname_matcher.assign("boost_");
      }

      regex_replace(std::back_inserter(v2), v1.begin(), v1.end(), libname_matcher, m_namespace_name + "_");
      std::swap(v1, v2);
      v2.clear();

      std::ofstream os;
      if(m_unix_lines)
         os.open((m_dest_path / p).c_str(), std::ios_base::binary | std::ios_base::out);
      else
         os.open((m_dest_path / p).c_str(), std::ios_base::out);
      os.write(&*v1.begin(), v1.size());
      os.close();
   }
   else if(m_namespace_name.size() && m_lib_names.size() && is_jam_file(p))
   {
      static std::vector<char> v1, v2;
      v1.clear();
      v2.clear();
      std::ifstream is((m_boost_path / p).c_str());
      std::copy(std::istreambuf_iterator<char>(is), std::istreambuf_iterator<char>(), std::back_inserter(v1));

      static boost::regex libname_matcher;
      if(libname_matcher.empty())
      {
         std::string re = "\\<";
         re += *m_lib_names.begin();
         for(std::set<std::string>::const_iterator i = ++m_lib_names.begin(); i != m_lib_names.end(); ++i)
         {
            re += "|" + *i;
         }
         re += "\\>";
         libname_matcher.assign(re);
      }

      regex_replace(std::back_inserter(v2), v1.begin(), v1.end(), libname_matcher, get_new_library_name(m_namespace_name));
      std::swap(v1, v2);
      v2.clear();

      std::ofstream os;
      if(m_unix_lines)
         os.open((m_dest_path / p).c_str(), std::ios_base::binary | std::ios_base::out);
      else
         os.open((m_dest_path / p).c_str(), std::ios_base::out);
      os.write(&*v1.begin(), v1.size());
      os.close();
   }
   else if(m_namespace_name.size() && is_source_file(p))
   {
      //
      // v1 hold the current content, v2 is temp buffer.
      // Each time we do a search and replace the new content 
      // ends up in v2: we then swap v1 and v2, and clear v2.
      //
      static std::vector<char> v1, v2;
      v1.clear();
      v2.clear();
      std::ifstream is((m_boost_path / p).c_str());
      std::copy(std::istreambuf_iterator<char>(is), std::istreambuf_iterator<char>(), std::back_inserter(v1));

      static const boost::regex namespace_matcher(
         "(?|"
            "(namespace\\s+)boost(_\\w+)?(?:(\\s*::\\s*)phoenix)?"
         "|"
            "(namespace\\s+)(adstl|phoenix|rapidxml)\\>"
         "|"
            "()\\<boost((?:_(?!intrusive_tags)\\w+)?\\s*(?:::))(?:(\\s*)phoenix)?"
         "|"
            "()\\<((?:adstl|phoenix|rapidxml)\\s*(?:::))"
         "|"
         "(namespace\\s+\\w+\\s*=\\s*(?:::\\s*)?)boost(_\\w+)?(?:(\\s*::\\s*)phoenix)?"
         "|"
            "(namespace\\s+\\w+\\s*=\\s*(?:::\\s*)?(?:\\w+\\s*::\\s*)?)(adstl|phoenix|rapidxml)\\>"
         "|"
            "(^\\s*#\\s*define\\s+\\w+\\s+)boost((?:_\\w+)?\\s*)$"
         "|"
            "(^\\s*#\\s*define[^\\n]+)((?:adstl|phoenix|rapidxml)\\s*)$"
         "|"
            "()boost(_asio_detail_posix_thread_function|_regex_free_static_mutex)"
         "|"
            "()(lw_thread_routine|at_thread_exit|on_process_enter|on_process_exit|on_thread_enter|on_thread_exit|tss_cleanup_implemented)"
         "|"
            "(BOOST_CLASS_REQUIRE4?[^;]*)boost((?:_\\w+)?\\s*,)"
         "|"
            "(\\(\\s*)boost(\\s*\\))"
         ")"
      );

      regex_replace(std::back_inserter(v2), v1.begin(), v1.end(), namespace_matcher, "$1" + m_namespace_name + "$2(?3$3" + m_namespace_name + "phoenix)", boost::regex_constants::format_all);
      std::swap(v1, v2);
      v2.clear();

      if(m_namespace_alias)
      {
         static const boost::regex namespace_alias(
            /*
            "namespace\\s+" + m_namespace_name + 
            "\\s*"
            "("
               "\\{"
               "(?:"
                  "(?>[^\\{\\}/]+)"
                  "(?>"
                     "(?:"
                        "(?1)"
                        "|//[^\\n]+$"
                        "|/[^/]"
                        "|(?:^\\s*#[^\\n]*"
                           "(?:(?<=\\\\)\\n[^\\n]*)*)"
                     ")"
                     "[^\\{\\}]+"
                  ")*"
               ")*"
               "\\}"
            ")"
            */
            /*
            "(namespace\\s+" + m_namespace_name + 
            "\\s*\\{.*"
            "\\})([^\\{\\};]*)\\z"
            */
            "namespace\\s+" + m_namespace_name + 
            "\\s*\\{"
            );
         regex_replace(std::back_inserter(v2), v1.begin(), v1.end(), namespace_alias, 
            "namespace " + m_namespace_name + "{} namespace boost = " + m_namespace_name + "; namespace " + m_namespace_name + "{");
         std::swap(v1, v2);
         v2.clear();
      }

      std::ofstream os;
      if(m_unix_lines)
         os.open((m_dest_path / p).c_str(), std::ios_base::binary | std::ios_base::out);
      else
         os.open((m_dest_path / p).c_str(), std::ios_base::out);
      if(v1.size())
         os.write(&*v1.begin(), v1.size());
      os.close();
   }
   else if(m_unix_lines && !is_binary_file(p))
   {
      std::ifstream is((m_boost_path / p).c_str());
      std::istreambuf_iterator<char> isi(is);
      std::istreambuf_iterator<char> end;

      std::ofstream os((m_dest_path / p).c_str(), std::ios_base::binary | std::ios_base::out);
      std::ostreambuf_iterator<char> osi(os);

      std::copy(isi, end, osi);
   }
   else
   {
      // binary copy:
      fs::copy_file(m_boost_path / p, m_dest_path / p);
   }
}